Liquid level regulating system

ABSTRACT

A liquid level regulating system according to this disclosure includes a duct having a termination in a container, the liquid level of which is to be regulated. The termination of the duct is normally just below the intended liquid level. A fluid displaceable element is in fluid communication with the duct. Electromechanical means is activated by a source of pulsating current to urge the fluid displaceable element into reciprocation. One feature resides in the provision of a plurality of ducts for sensing liquid level, and another feature resides in the use of a valve between the reservoir and the fluid displaceable element for controlling the flow of fluid therebetween.

United States Patent [72] inventor [21] App]. No.

[22] Filed [45] Patented [54] LIQUID LEVEL REGULATING SYSTEM 22 Claims, 12 Drawing Figs.

[52] U.S.Cl 4l7/211.5, 417/326, 417/549, 417/550 [51] Int. Cl. F04b 49/00, F04b 35/04 [50] Field olsearch 417/21 1.5, 214, 326, 36, 39,549, 550, 553

[56] References Cited UNITED STATES PATENTS 730,465 6/1903 Ladislaw et al 417/21 1.5 440,218 11/1890 Bessonoff..... 103/35 2,801,591 8/1957 Parker 103/38 3,118,383 1/1964 Woodward 103/53 3,194,446 7/1965 Miller 103/178 3,221,798 12/1965 Kofink 103/53 3,319,577 5/1967 Herreshoff 103/178 3,381,616 5/1968 Wertheimer 103/53 3,411,704 ll/l963 Hilgert et a1. 230/55 Primary Examiner-William L. Freeh Attorney-Angus and Mon ABSTRACT: A liquid level regulating system according to this disclosure includes a duct having a termination in a container, the liquid level of which is to be regulated. The termination of the duct is normally just below the intended liquid level. A fluid displaceable element is in fluid communication with the duct. Electromechanical means is activated by a source of pulsating current to urge the fluid displaceable element into reciprocation. One feature resides in the provision of a plurality of ducts for sensing liquid level, and another feature resides in the use of a valve between the reservoir and the fluid displaceable element for controlling the flow of fluid therebetween.

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LIQUID LEVEL REGULATING SYSTEM This invention relates to pumps, and to liquid level regulating systems and pumps therefor.

In my Pat. No. 3,134,332, granted May 26, 1964, there is described a liquid level regulating system in which a fluid displaceable element in the form of ,a diaphragm is in fluid communication through a duct with a container containing liquid, the level of which is to be regulated. The diaphragm is coupled to a pumping element which is supplied with liquid from a reservoir. When the liquid level is below the duct opening in the container, a pulsating force is applied to the diaphragm which likewise pulsates and causes the pumping element to pump liquid from the reservoir and through the duct into the container. When the level of liquid in the container rises above the duct opening, the liquid closes the duct and prevents further pumping by opposing the fluid displacement of the diaphragm.

In my earlier patent the pulsating force is derived from a pulsating pressure, which, in the case of a system for regulating the level of oil in the crankcase of an engine or compressor, was derived from the pulsating pressure cycle within the crankcase, which is applied to the diaphragm through the duct itself.

In the present invention, pump and regulating means are provided with a fluid displaceable element in fluid communication with the liquid in the container, the level of which is to be regulated. A source of pulsating force independent of pumping action is applied to urge mechanically the fluid displaceable element in reciprocation and is activated by a source of varying electric current. When the termination of the duct connecting the fluid displaceable element with the container is above the level of the liquid therein, the duct may freely breathe the atmosphere of the container above the liquid and the fluid displaceable element may freely follow the urging of the pulsating force. When the termination is submerged, the liquid closes the duct and interrupts breathing, thereby greatly reducing the motion of the fluid displaceable element.

When the system of my earlier patent is applied to a condition of varying rate of pulse repetition, for example, to the crankcase of an internal combustion engine of varying speed, a problem arises due to the variation in rate of the pulse. For such conditions, it became necessary to accurately size the duct and duct termination so as to permit adequate breathing at high speeds, but to be sufficiently restricted to prevent excessive motion of the fluid displaceable element at low speeds. Although in practice careful control of sizes will ordinarily result in a system which would satisfy both requirements, the necessity for careful sizing of both duct and termination is costly and has been a limitation on the broadest use of my earlier system.

It is an object of this invention to provide a pump of the same class as that described in my prior patent wherein a constant source of pulsating force is applied to a fluid displaceable member.

It is a further object of this invention to provide electromechanical means for pulsating the fluid displaceable element of a pump of the same class as that described in my prior patent.

In a regulating system according to my earlier patent, a differential pressure cycle operated the fluid-displaceable element; it was not possible to operate the apparatus if the same pressure is applied to both sides of the element simultaneously. However, according to my present invention, the same fluid pressure may be applied to both sides of the fluid-displaced element permitting regulation of level with a container at pressures substantially higher or lower than available at other reference levels of pressure, such as atmospheric pressure. This feature is made possible because my electromechanical pulsating means is applied independently of fluid pressure pulsations.

In an important variation, I may choose to bring both sides of the fluid-displaceable element into communication with the container, each through a separate duct which terminates at liquid level. When both of the terminations are exposed, liquid is pumped through one duct into the container; but when one or both tenninations are submerged, further delivery of liquid is prevented. By placing these terminations at separate places, it becomes possible to cut off delivery when the container, for any reason, departs greatly from its original attitude. This feature is of particular advantage in some mobile applications of the system according to my present invention, such as marine and land vehicles uses in equipment which may, for brief periods of time, take on extreme attitudes.

It is an optional and desirable feature of my present invention to provide equalization of pressures prevailing on both sides of a fluid-displaceable element of a pump of the same class as that described in my earlier patent.

Another optional but desirable feature of my presentinvention is to provide a plurality of regulating ducts for a pump to permit control of liquid delivery at different terminating positions.

In my earlier patent the pumping means and the fluid-displaceable member are loosely coupled thereby permitting some motion of the fluid-displaceable element without corresponding motion of the pumping element. This permits the relatively small residual motion of the fluid-displaceable element which may occur during cutofl by immersion of the regulating duct termination without causing unwanted delivery of liquid to the container. I have, however, found that sometimes the pumping element tends to follow the motion of the fluid-displaceable element before the fullest possible extent of the lost motion has developed.

Still another optional feature of my present invention is to provide fluid pressure valving means in association with the pumping means which requires a design force being commencing pumping action, thereby avoiding premature pumping of the pumping element.

The above and other features of this invention will be more fully understood from the following detailed description and the accompanying drawings, in which:

FIG. 1 is a schematic mechanical diagram of a pump and liquid level regulating system in accordance with the presently preferred embodiment of the present invention;

FIG. 2 is a side view elevation, partly in cutaway cross section, of a pump according to the presently preferred embodiment of the present invention for use in the system illustrated in FIG. 1;

FIG. 3 is a side view elevation, partly in cutaway cross section, of a pump in accordance with a modification of the present invention;

FIG. 4 is a side view elevation, partly in cutaway cross section of a pump in accordance with another modification of the present invention;

FIGS. 5 through 9, inclusive are circuit diagrams of various regulating circuits for use with a pump in accordance with the present invention.

FIG. 10 is a schematic mechanical view of a pump and liquid level regulating system in accordance with a modification of the invention illustrated in FIG. 1;

FIG. 11 is a view taken at line 11-11 in FIG. 10, and

FIG. 12 is another schematic mechanical view of a pump and liquid level regulating system in accordance with another modification of the present invention.

Referring to the drawings, and particularly to FIG. 1 there is illustrated a block diagram of a regulating system in accordance with the presently preferred embodiment of the present invention. The system illustrated in FIG. 1 comprises a pump 10 having a first fluid conduit 11 in fluid communication with a reservoir 12 containing fluid l3, and a second fluid conduit 14 in fluid communication with a container 15. The liquid level 16 of fluid within container 15 is to be regulated and maintained at approximately the level illustrated in the drawing. Electrical cable 17 electrically connects pump 10 with electrical regulator 18, which in turn is connected to battery 19 by suitable wires 20 and 21. Regulator 18 may be any suitable source of pulsating current. For example, regulator 18 and battery 19 may be a motor operated alternator. Indicator lamp 22 may be connected across regulator 18 to indicate the operation of the regulator. Preferably, switch 23 is included in the circuit to selectively provide power to the regulator. By way of example, switch 23 may be the ignition switch or other suitable switch device for a motor vehicle. Pump is also in fluid communication with the pressure in container above liquid level 16 through fluid conduit 24. As will be more fully understood hereinafter, conduit 24 may also be in fluid communication with the atmosphere if the pressure in container 15 is of the same order as atmospheric pressure.

Preferably, fluid conduit 14 is in fluid communication with duct 26 which is fixedly mounted within container 15. By way of example, container 15 may comprise the crankcase of an internal combustion engine in which it is desired to maintain the liquid level of oil 16 at the level illustrated in the drawings. Duct 26 includes a terminal opening 27 disposed just below the desired liquid level of the oil.

In FIG. 2 there is illustrated a pump 10a in accordance with the presently preferred embodiment of the present invention; pump 10a may be used for pump 10 in FIG. 1. Pump 10a includes a first housing 30, a diagram 31 and a second housing 32 assembled together by means (not shown) so that the diaphragm is sandwiched between housings and 32. Cap 33 is sealed to one end of housing 32 by seal 34. Pump mechanism 35 includes a valve housing 36 supported by housing 32 and extending into the region defined by seal 34 and cap 33. Bolt 37, together with spacer 38 and seal 39 is threadably assembled into valve housing 36 to hold cap 33 in place. Screen 33' may be provided to filter foreign particles from the fluid.

Pump 100 further includes a first chamber 40 defined by housing 32 and diaphragm 31 and a second chamber 41 defined by housing 30 and diaphragm 31. A third chamber 42 is defined between cap 33 and housing 32. The threaded port opening 43 is provided in housing 32 in fluid communication with chamber 40. A second threaded port opening 44 is formed in housing 32 in fluid communication with chamber 42.

Diaphragm 31 is sandwiched between plates 45 and 46 which in turn are fastened together by rivets 47. The plates and diaphragm are so arranged and disposed as to provide movement thereof along axis 48 of the valve. Plate 46, together with diaphragm 31 forms cavity 49 adapted to loosely receive head 50 of piston housing 51. Piston housing 51 includes port openings 52 providing fluid communication between chamber 40 and the interior bore of housing 36. Valve head 53 has its shank 54 fixedly mounted to piston housing 51. O-ring seal 55 provides a fluid seal between valve head 53 and the interior bore of valve housing 36. O-ring seal 55 is biased downwardly against valve head 53 by means of compression spring 56 and spacer ring 57.

Valve housing 36 further includes port opening 63 providing fluid communication between chamber 42 and the lower portion of valve mechanism 35. Valve 61 includes valve head 62 carrying seal 58 which is nonnally biased against valve seat 59 by means of bias spring 60.

Port opening is disposed within housing 30 and provides fluid communication to chamber 41. Mounted within chamber 41 is solenoid 71 having a frame 72 fastened to housing 30 by means of fasteners 73 and 74. Solenoid 71 includes a electric coil 75 connected by means of suitable electrical wires to cables 17 (see FIG. 1). An iron core 76 is supported by Teflon ring bearings 77, 77' in chamber 78 which is surrounded by coil 75. Core 76 is fastened to plate 45 by means of threaded fastener 79. Compression spring 80 is disposed between plate 45 and solenoid housing 72 to urge diaphragm 31 downwardly to the position illustrated in FIG. 2.

FIG. 3 illustrates a modification of the pump in accordance with the present invention which may be used for pump 10 in FIG. 1, wherein pump 10b comprises a housing 32 similar to housing 32 illustrated in FIG. 2. Pump mechanism 35 includes valve housing 36 in the manner heretofore described in connection with FIG. 2, and port 44 provides fluid communication to cavity 42 for providing an inlet of fluid to be pumped. Port 43 provides fluid communication to chamber 40 as heretofore described. Piston housing 51 is assembled to valve mechanism 35 and to plate 46 to operate on diaphragm 31, as heretofore described. The difference of the pump illustrated in FIG. 3 from that illustrated in FIG. 2 resides primarily in the construction of the portion of the pump above diaphragm 31. As in the case of the embodiment illustrated in FIG. 2, the diaphragm is sandwiched between plates 46 and 45. Housing is assembled (by means not shown) to the diaphragm and includes inlet ports 91 and 92 which provide fluid communication to chamber 41 above the diaphragm.

Solenoid 93 comprises a frame 94 fastened to housing 90 by means of fastener 95. The solenoid further includes winding 96 disposed about cylindrical housing 97 which in turn is supported by housing 90 at the lowermost portion thereof. Iron core 98 is disposed within cylindrical housing 97 and is journaled thereto by Teflon bearings 99,99. Core 98 is fastened to plate 45 by means of threaded fastener 100. O-ring seal 101 provides a fluid seal between housing 97, housing 90 and housing 94.

As illustrated in FIG. 3, solenoid 93 is disposed within chamber 102 formed by cap 103. Cap 103 is assembled to the pump by means of threaded fastener 104 being threaded to the solenoid housing 94. Threaded port opening 105 is provided for permitting connection of electrical cables to winding 96 of the solenoid. Spring 106 is disposed between wall 107 of housing 90 and plate 45 to normally bias plate 45 downwardly to the position illustrated in FIG. 3.

One feature of the pump illustrated in FIG. 3 is that the electrical connections for solenoid 93 are sealed from any communication with either chamber 41 or 40, and thus are sealed from damage due to oil and the like. The fluid seal is provided by means of wall 107 of housing 90 and the fluid seal 101 between housing 90 and housing 97. Relief port 98' is provided in core 98 to permit air to flow in the chamber formed by housing 97 so that core 98 may freely move in the chamber under the influence of the magnetic circuit.

FIG. 4 illustrates another modification of a pump 100 for use as pump 10 in FIG. 1 in accordance with the present invention. The portion of pump 10c below diaphragm 31 is primarily the same as that illustrated in FIGS. 2 and 3, an reference may be had to those FIGS. for a more complete description thereof. The primary difierence between the pump illustrated in FIG. 4 and that illustrated in either of FIGS. 2 or 3 is that instead of pulling the diaphragm upwardly and relying on a spring bias to return it to the original position as in the pumps illustrated in FIGS. 2 and 3, in FIG. 4 the solenoid pushes the diaphragm downwardly and a spring is utilized to return it to the position illustrated in the Figure. Hence, in FIG. 4, shoulder 110 is provided so housing 32 in chamber 40, and compression spring 11 1 is provided between shoulder 110 and plate 46 of the diaphragm. Housing 112 forms cavity 41 and includes port opening 113 in fluid communication therewith. Housing 112 is sealed by means of O-ring seal 114 to cylindrical housing 115. Housing 115 supports iron core 116 which is journaled by means of Teflon bearings 117, 117' thereto. Housing 115 is also sealed by means of O-ring seal 1 18 to cap 119. Cap 119 defines, with housing 112, cavity 120 which contains solenoid 121.

Solenoid 121 comprises solenoid frame 122 which is fastened to housing 112 by means of fasteners 123 and is fastened to cap 119 by means of fasteners 124. Solenoid 121 further includes an electric winding 125 wrapped around cylindrical housing 115. As illustrated in FIG. 4, the lowermost portion of core 116 is contiguous to the upper surface of plate 45. Also, threaded port openings 126 and 127 provide fluid communication to cavity 120 for connection of electrical cables to the solenoid winding.

With reference to FIGS. 1 and 2, the operation of the pump and liquid level regulating system may be readily explained. Probe or duct 26 is inserted into the container 15 containing liquid whose level is to be regulated so that opening 27 of probe 26 is disposed just below the normal liquid level 16 of the liquid. By way of example, in the case of an internal combustion engine wherein the oil level in the crankcase has to be regulated, probe 26 is inserted into the crankcase so that opening 27 is just below the normal level of the oil. Probe 26 is in fluid communication through hose or conduit 14 through elbow 131 which is threadably assembled to threaded port opening 43. Tube 132 is inserted into reservoir 12 containing liquid 13 so that it is open at the lowest portion of reservoir 12. Tube 132 is in fluid communication with pump through flexible conduit 11 which is threadably assembled through fitting 133 to threaded opening 44. Threaded opening 70 is in fluid communication with a source of pressure, such as the atmosphere, but as will be more fully understood hereinafter, threaded opening 70 may be in fluid communication with a probe such as probe 26 located in another portion of the crankcase l5. Wires 134 and 135 of cable 17 are connected to winding 75 of solenoid 71. Wires 134 and 135 are electrically connected to regulator 18.

Assuming that the liquid level 16 of liquid within crankcase is below opening 27 so that opening 27 is exposed to the air above the liquid, the operation of the regulating system may be explained. Regulator 18 provides a pulsating current to the winding of solenoid 71 within pump 10. Upon each pulse of current, solenoid 71 operates on core 76 to pull the core upwardly along axis 48 of the pump, thereby compressing spring 80 and drawing diaphragm 31 upward. The upward movement of the diaphragm 31 pulls on piston head 50 thereby pulling piston housing 51 upwardly along axis 48. The movement of piston housing 51 in an upward direction reduces the pressure below piston 53, and oil which is admitted through opening 44 into cavity 42 and port 63 pushes upwardly on valve 61 thereby displacing seal 58 from valve seat 59. Thus, during the upward stroke of the solenoid, oil or fluid is permitted to flow into the region defined by valve housing 36 which is below piston 53.

When current pulse is ended, spring 80 urges diaphragm 31 downwardly along axis 48. Piston housing 51 is urged downwardly as is piston 53. HOwever, due to the increased pressure below piston 53 and above head 62, head 62 seals with sea] 58 against valve seat 59 to prohibit oil from returning to chamber 42. The increased pressure below piston 53 reacts against seal 55 thereby displacing seal 55 from piston 53, and thereby permitting oil to enter the region between seal 55 and piston 53. When the pressures have again equalized, spring 56 urges seal 55 back downwardly against head 53.

Upon the next upward stroke of core 76 (during the next current pulse on solenoid winding 75), the oil trapped in piston housing 51 by seal 55 rides upwardly so that upon the next downward stroke as more oil enters between piston 53 and seal 55, oil is forced out through aperture 52 into chamber 40. Oil is then permitted to drain through port 43 with each successive operation of the solenoid. Oil pumped through port 43 flows through fluid conduit 14 and into the crankcase through probe 26.

In the event that opening 27 of probe 26 is submerged below the liquid level 16 of the oil, no additional oil will be pumped. The reason for this is that when opening 27 is blocked, the movement of diaphragm 31 is restrained due to the closed pressure system on one side of the diaphragm. Pressure within chamber 40, not being vented to the atmosphere through opening 27, prevents oil from being pumped through port 63 into chamber 40. Since chamber 40 is not vented to the atmosphere through opening 27, movement of diaphragm 31 is dampened by virtue of the static pressure. Actually, some movement of the diaphragm 31 may occur by virtue of the current surges in winding 75 and the associated effect on core 67, but piston housing 51 is loosely joumaled to plate 46 so that insignificant movement of diaphragm 31 does not effect movement of piston housing 51. Also, by virtue of the dual valves 53 and 61 between chambers 42 and 40, positive action of the diaphragm with sufficient force to overcome the associated spring biases is necessary to operate the pump.

As heretofore mentioned, an additional probe such as illustrated at 26 may be operatively associated with threaded port opening 76. Hence, as will be more fully understood hereinafter, if an additional probe at another location of the crankcase is in fluid communication with chamber 41 through threaded opening 70, a pumping action will not occur unless both probes are exposed to the atmosphere. In the event that only one probe becomes exposed to the atmosphere. such as may be occasioned by a rolling motion of the engine, additional fluid will not be pumped because movement of the diaphragm 31 is substantially resisted by virtue of the closed pressure of at least one side of the diaphragm.

The pump illustrated in FIG. 3 operates in the same manner as that illustrated in FIG. 2 except that in FIG. 3 the electrical connections to the solenoid are not in fluid communication with upper chamber 41. Hence, chamber 102 through which the electrical connections to the solenoid are made, is fluid sealed from chamber 41. However, as in the case of the pump illustrated in FIG. 2, fluid is pumped through aperture 43 by a pulsating current operating on core 98.

The pump illustrated in FIG. 4 is similar to that illustrated in FIGS. 2 and 3 except that for each pulsating current, the core is moved downwardly to compress spring 111 on the downward side of the diaphragm. Upon release of the current surge, spring 111 urges diaphragm 31 back upwardly.

FIGS. 5 through 9 illustrate typical circuit diagrams of a current regulator 18 for use with the present invention for providing a pulsating current. In FIG. 5 regulator 18a, which may be used for regulator 18 in FIG. 1, comprises a multivibrator 136 which is connected through resistor 137 to the wire 20 which in turn is connected to the positive side of battery 19 (FIG. 1). The multivibrator is also connected to lead 21 which in turn is connected to the negative side of battery 19.

Multivibrator 136 is a free running astable multivibrator and comprises a first NPN-transistor 138 and a second NPN- transistor 139. The base of transistor 138 is connected through resistor 140 to one side of resistor 137. The base of transistor 138 is also connected through capacitor 141 and resistor 142 to the collector of transistor 139. Likewise the base of transistor 139 is connected through resistor 143 to the one side of resistor 137 and is connected through capacitor 144 and resistor 145 to the collector of transistor 138. Resistors 142 and 145 are connected together through series capacitors 146 and 147, and the junction between these capacitors is connected to the emitter of transistor 138 which in turn is connected to lead 21. The collector of transistor 138 is also connected to resistor 137 through resistor 148, and the collector of transistor 139 is connected to resistor 137 through resistor 149.

The output of multivibrator 136 is taken from the emitter of transistor 139 which is connected to the base of NPN- transistor 150. The collector of transistor 150 is connected to lead 20 through resistor 151 and is connected to the base of NPN-transistor 152. The emitter of transistor 150 is connected to lead 21. The emitter of transistor 152 is connected to the base of NPN-transistor 153 whose emitter is connected to lead 21 and whose collector is connected to one side of resistor 154. The collector of transistor 152 is connected to the opposite side of resistor 154 to lead 135. The collector of transistor 152 is also connected through diode 155 to lead 134 which is directly coupled to lead 20.

In operation of the circuit illustrated in FIG. 5, when a direct current is applied to leads 20 and 21, free running multivibrator 136 operates to provide positive pulses to the base of transistor 150. Transistor 150 operates on transistor 152 which in turn operates on transistor 153 to thereby provide battery current through resistor 154 to lead 135 at a voltage determined by a small drop across resistor I54. Lead 134 is directly connected to lead 20. Hence, pulsating current is provided to the output leads 134 and 135 which in turn are connected to the solenoid of the pump illustrated in FIGS. 2-4. Diode 155 is provided to short out inverse voltage transients between leads 134 and 135.

One feature of the multivibrator circuit resides in the fact that capacitors 146 and 147, together with resistors 142 and 145, function as RC filters to suppress transient voltages which might otherwise prematurely switch the mode of the multivibrator. Also, transistor 153 is protected by load resistor 154 which provides most of the load between input lead 21 and output lead 135. Preferably, the drop across the serial arrangement of the collector-to-emitter of transistor 153 and resistor 154 is made approximately equal to the drop across the serial arrangement of the emitter-to-base of transistor 153 and the collector-to-emitter of transistor 152. Since the two paths are parallel, the drop across the collector-to-emitter circuit of transistor 153 is minimized.

FIG. 6 illustrates a modification of a regulator 18b in accordance with the present invention, which may be used for regulator 18 in FIG. 1, wherein multivibrator 136 is connected between leads 20 and 21 and the output of multivibrator 136 is connected to the base of NPN-transistor 160. The emitter of transistor 160 is connected to the base of NPN-transistor 161 whose emitter is connected to lead 21. The collector of transistor 160 is connected through resistor 162 to lead 20, and the collector of transistor 161 is connected to lead 135. Diode 163 is connected between leads 134 and 135, lead 134 being directly coupled to lead 20.

FIG. 7 illustrates yet another modification of a regulator 180 in accordance with the present invention which may be used for regulator 18 in FIG. 1, wherein multivibrator 136 is connected to lead 21 and through resistor 164 to lead 20. The output of multivibrator 136 is connected to the base of NPN- transistor 165 whose emitter is connected to lead 21 and whose collector is connected to the base of NPN-transistor 166 and to resistor 167. The opposite side of resistor 167 is connected to lead 20, and the emitter of transistor 166 is connected to lead 20, and the emitter of transistor 166 is connected to lead 21. The collector of transistor 166 is connected to the output lead 135 which is referenced to output lead 134 through diode 168. Output 134 is directly coupled to lead 20.

The circuits illustrated in FIGS. 6 and 7 operate in basically the same manner wherein the output transistor 160 or 165 drives a second transistor, 161 or 166 to allow line currents to be passed to the output leads. Diodes 163 and 168 are provided to dissipate current surges.

FIG. 8 illustrates another regulator for use as regulator 18 in FIG. 1 which utilizes an alternating current source for deriving the pulsating current for driving the solenoid of the pump. In FIG. 8, regulator 18d comprises multivibrator 136 connected to lead 169. Multivibrator 136 is also connected to lead 134 through resistor 170 and diode 171. Capacitor 172 is connected across multivibrator 136 to filter the current rectified by diode 171. Lead 134 is connected through diode 173 to terminal 174. A source of alternating current 175, such as ordinary 60 cycle, 115 volt, alternating current may be connected to terminal 174.

The output of multivibrator 136 is connected through resistor 176 to lead 169 and is connected to the base of NPN- transistor 177. The emitter of transistor 177 is connected to lead 169 and the collector of transistor 177 is connected through resistor 178 to one side of four-layer diode 179. The junction between resistor 178 and four-layer diode 179 is also referenced to lead 169 through capacitor 180. The opposite side of capacitor 180 is connected through resistor 181 to the opposite side of four-layer diode 170. The junction between resistor 178, four-layer diode 179 and capacitor 180 is referenced to lead 135 through resistor 182. The junction between resistor 181 and four-layer diode 179 is connected to the gate of silicon-controlled rectifier 183. The cathode of silicon-controlled rectifier 183 is connected to lead 169 while the anode of SCR 183 is connected to output lead 135. Output lead 135 is referenced to output lead 134 through diode 184.

In operation of the circuit illustrated in FIG. 8, alternating current supplied by source 175 is rectified through diode 173 to provide a pulsating current on lead 134. This current is also rectified through diode 171 to provide a direct current to multivibrator 136 which is filtered by capacitor 172. Multivibrator 136 provides a pulsating output current to transistor 177 which in turn operates through resistor 178 on capacitor 180. The RC time delay circuit provided by resistor 182 and capacitor 180 operates on four-layer diode 179 in such a manner that when the current across capacitor 180 builds up to the breakdown level of four-level diode 179, capacitor 180 discharges through diode 179 to operate on the gate of SCR 183 to bias SCR 183 into conduction thereby permitting current to flow between leads 169 and 135. Diode 184 is provided to dissipate current surges between leads 134 and 135.

FIG. 9 illustrates still another circuit 18e for supplying pulsating current to the solenoid of a pump. Alternator 190 has its output connected through diode 191 to terminals 134 and which are connected to the solenoid as hereinbefore described. Alternator 190, which may, for example, be a motor driven alternator driven by the motor or engine whose oil level is being regulated, provides an alternating current output which is half-wave rectified by diode 191 to provide a pulsating half-wave signal at terminals 134 and 135.

In operation of the system illustrated in FIG. 1, the resistors in multivibrator 36 in regulator 18, and particularly resistors 140, 143, 148 and 149 (see FIG. 5), are adjusted so that multivibrator 136 produces output pulses at a constant frequency. The frequency of the signals produced by multivibrator 136 is adjusted to have the optimum effect on the fluid-displaceable element, diaphragm 31 of pump 10. Ordinarily, for most cases, a frequency of about 5 cycles per second will be adequate. The signal is applied to operate the switching elements illustrated in the respective circuit diagrams, FIGS. 5 through 8, inclusive, so as to impose a signal of the same frequency on output lines 134 and 135 which in turn drives the solenoid winding. For a signal having a frequency of 5 cycles per second, the solenoid winding is energized 300 times per minute so as to provide 300 reciprocal movements of the associated core. Hence, diaphragm 31 is at 300 cycles per minute. The reciprocation of diaphragm 31 is independent of the crankcase pressure cycle within the engine and hence, the liquid level regulating system operates in a continuous manner regardless of whether the motor is idling at a relatively slow speed or at a relatively fast speed.

FIGS. 10 through 12 illustrate modifications of a liquid level regulating system in accordance with the present invention. In FIGS. 10 and 11, pump 10d is provided with an inlet 11 which is in communication with a reservoir of liquid (not shown). Cable 17 is connected to the solenoid within the housing of the pump 10d Pump 10d is provided with a pair of outlet conduits 14 and 14a, outlet conduit 14 being in fluid communication with the lower chamber 40 (see FIGS. 3-5 of housing 101! (below diaphragm 31) and outlet 14abeing in fluid communication with chamber 41 (see FIGS. 3-5) above the diaphragm in housing 10d. Outlet conduits 14 and are connected to respective probes 26 and 26a whose terminations 27 are disposed below the normal liquid level 16 of liquid within container 15 whose liquid level is to be regulated.

In operation of the regulating system illustrated in FIGS. 10 and 11, if the liquid level 16 within container 15 is above the terminations 27 of either or both probes 26 and 26a, pump 10d is unable to pump liquid into the container through conduit 14 and probe 26 because the chamber on one or both sides of the diaphragm within housing 10d is a closed chamber and hence the diaphragm cannot pulsate. Thus, if one probe should become exposed, but not the other, as may be occasioned by a rolling maneuvering of the vehicle to which the liquid level regulating system is attached, no fluid will be pumped into container 15 because the diaphragm is restricted from moving by virtue of the closed chamber on one side of the diaphragm or the other. However, in the event that the terminations of both probes 26 and 26a become exposed above the liquid level 16, fluid from the source (not shown) is pumped through conduit 11 and conduit 14 through probe 26 and into container 15.

FIG. 12 illustrates another modification of the liquid level regulating system in accordance with the present invention wherein housing We is provided with an inlet conduit 11 attached to a suitable reservoir of fluid (not shown). Cable 17 provides electrical connections from the regulating circuit (not shown) to the solenoid within housing c. Conduit i4 is connected to the chamber 41 (See FIGS. 3-5) within housing 10 on the opposite side of the diaphragm from chamber 40 (FIGS. 3-5) associated with inlet conduit 11. Conduit 14 is connected to probe 26 whose termination 27 is disposed below the normal liquid level 16 of the liquid within container 15. Outlet opening 195 is in fluid communication with lower chamber 40 (FIGS. 3-5) of pump lltle. in operation of the system illustrated in FIG. 12, if termination 27 of probe 26 should become exposed above the liquid level 16 of the liquid within container whose liquid level is to be regulated, the upper chamber 41 of the housing above the diaphragm becomes exposed to the atmosphere. The lower chamber 40 of the housing below the diaphragm is already exposed to the atmosphere through outlet opening 195. Hence, the pump is free to pump liquid from the reservoir (not shown) through conduit 11 and opening 195 through the wall of container 15. Hence, fluid is dispensed into the container to raise the liquid level therein. In the system illustrated in FIG. 12, fluid is not pumped through the conduit 14 and probe 26 and conduit 14 and probe 26 are utilized for determining the level of the liquid within the container.

The present invention thus provides apparatus for regulating the liquid level in a container which is effective in operation and requires little maintenance. The use of an electromechanical pulsating device providing the pulsating force to a fluid-displaceable member provides greater accuracy and control over the pumping action of the apparatus heretofore available.

This invention is not to be limited by the embodiments shown in the drawings and described in the description, which are given by way of example and not of limitation.

We claim:

1. Apparatus comprising: a duct having a termination at a location in a container containing liquid and a compressible gas above said liquid, said termination being in fluid communication with said liquid and may or may not be submerged by said liquid according to the level of the liquid surface in said container; a reciprocable element in fluid communication with said duct, said reciprocable element being in fluid communication with a compressible gas in said duct during normal operating conditions; and a source of pulsating force adapted to urge said element in reciprocation, said source including electromechanical means responsive to a varying current for urging said element in reciprocation and current varying means connected to said electromechanical means for supplying a varying current to said electromechanical means, said varying current varying at such a frequency that said reciprocable element is urged to reciprocate at such a rate as to apply a pulsating force on the fluid closing the termination end of said duct so that when the termination end of said duct is substantially submerged in liquid the pulsating force on the liquid closing the termination does not substantially displace the liquid closing the termination thereby impeding displacement of gas within said duct and impeding reciprocation of said element, and when the termination end of said duct is not substantially submerged in liquid the compressible gas in the duct is vented through said termination to the compressible gas above the level of the liquid surface in said container and said element is not substantially impeded from reciprocation.

2. Apparatus according to claim 11 wherein said duct is in fluid communication with the opposite side of said element from said reservoir, and outlet means in fluid communication with the same side of said element as said reservoir, said outlet means being in fluid communication with said container.

3. Apparatus according to claim I wherein said duct ascends from the level of liquid in said container.

4. Apparatus according to claim 1 wherein said duct is disposed in an attitude which lies in the range from one in which the termination is located vertically below the point of fluid communication of the duct with the reciprocable element to one in which the termination is located approximately at the same horizontal level as the point of fluid communication of the duct with the reciprocable element.

5. Apparatus according to claim 1 further including second duct means having a termination at a location in said container in communication with said liquid and which may or may not be submerged by said liquid according to the level of the liquid surfaces in said container, said second duct means being in fluid communication with said reciprocable element.

6. Apparatus according to claim 5 wherein said second duct means is in fluid communication with the opposite side of said reciprocable element from the first-named duct.

7. Apparatus according to claim 1 further including a reservoir, containing liquid pump means for regulating flow of liquid between said reservoir and said reciprocable element, said pump means including a housing having a bore having one end in fluid communication with said reservoir and the other end in fluid communication with said reciprocable element, piston means slidably mounted in said bore and coupled to said element for reciprocation with said element, seal means, and bias means for biasing said seal means against said piston means to provide a fluid seal between said piston means and said bore.

8. Apparatus according to claim 7, further including a valve seat in said bore between said piston means and said reservoir, valve means in said bore adapted to seal against said valve seat, and second bias means for biasing said valve means against said valve seat.

9. Apparatus according to claim 8 wherein said piston means is loosely coupled to said element so that said piston means does not reciprocate with minor fluctuations of said element.

10. Apparatus according to claim 7 wherein said piston means is loosely coupled to said element so that said piston means does not reciprocate with minor fluctuations of said element.

ll. Apparatus according to claim 1 wherein said electromechanical means includes a solenoid having a winding in electrical communication with said current varying means, a core magnetically coupled to said winding for urging said element in one direction upon energization of said winding, and bias means urging said element in the opposite direction.

12. Apparatus according to claim ll wherein said bias means is a spring.

13. Apparatus according to claim ll wherein said current varying means includes astable multivibrator means adapted to be connected to a source of current, and switch means operable by said multivibrator means for intermittently connecting said source of current to said winding.

14. Apparatus according to claim 13 wherein said switch means is a transistor.

15. Apparatus according to claim 13 wherein said switch means is a controlled rectifier.

16. Apparatus according to claim 15 wherein said controlled rectifier has a controllable element, and delay means connected to said controllable element and said multivibrator means.

17. Apparatus according to claim 13 further including means connected to said winding for dissipating current surges.

18. A system for regulating the level of liquid in fluid communication with said a container comprising a duct having a termination at a location in said'container in communication with said liquid and which may or may not be submerged by said liquid according to the level of the liquid surface in said container, a reservoir containing liquid, a reciprocable element in fluid communication with said duct, and a source of pulsating force adapted to urge said element in reciprocation, the improvement comprising: pump means controlling fluid communication between said reservoir and said element, said pump means including a housing having a bore having one end in fluid communication with said reservoir and the other end in fluid communication with said element, piston means slidably mounted in said bore and coupled to said element for reciprocation with said element, seal means, and bias means for biasing said seal means against said piston means to provide a fluid seal between said piston means and said bore, said piston means being loosely coupled to said element so that said piston means does not reciprocate with minor fluctuations of said element.

19. Apparatus according to claim 18 further including a valve seat in said bore between said piston means and said reservoir, valve means in said bore adapted to seal against said valve seat, and second bias means for biasing said valve means against said valve seat.

20. A system for regulating the level of liquid in a container comprising a first duct having a termination at a first location in said container in communication with said liquid and which may or may not be submerged by said liquid according to the level of the liquid surface in said container at said first location, a second duct having a termination at a second location in said container in communication with said liquid and which may or may not be submerged by said liquid according to the level of the liquid surface in said container at said second location, a reservoir containing liquid, a reciprocable element in fluid communication with said first and second ducts, and a source of pulsating force adapted to urge said element in reciprocation, the improvement comprising: pump means controlling fluid communication between said reservoir and said element, said pump means including a housing having a bore having one end in fluid communication including a housing having a bore having one end in fluid communication with said reservoir and the other end in fluid communication with said element, piston means slidably mounted in said bore and coupled to said element for reciprocation with said element, seal means, and bias means for biasing said seal means against said piston to provide a fluid seal between said piston means in said bore.

21. Apparatus according to claim 20 wherein said second duct means is in fluid communication with the opposite side of said element from the first-named duct.

22. A system for regulating the level of liquid in a container comprising a duct having a termination at a location in said container in communication with said liquid and which may or may not be submerged by said liquid according to the level of the liquid surface in said container, a reservoir containing liquid, a reciprocable element in fluid communication with said duct, a source of pulsating force adapted to urge said element in reciprocation, said duct being in fluid communication with the opposite side of said element from said reservoir, and outlet means in fluid communication with the same side of said element as said reservoir, said outlet means being in fluid communication with said container, the improvement comprising: pump means for controlling fluid communication between said reservoir and said element, said pump means including a housing having a bore having one end in fluid communication with said reservoir and the other end in fluid communication with said element, piston means slidably mounted in said bore and coupled to said element for reciprocation with said element, seal means, and bias means for biasing said seal means against said piston means to provide a fluid seal between said piston means and said bore.

23. Apparatus comprising: a container adapted to hold a body of liquid having a liquid level surface and a compressible gas above that surface, a reciprocable fluid displacement ele ment, a source of pulsating force adapted to urge said element in reciprocation, including a. electromechanical force means and b. current varying means for supplying a pulsating electric current to said electromechanical means, a duct adapted to receive the displacement of said element and having an open termination in sai d container which may or ma not be submerged by said liquid according to the level 0 said surface, said duct being normally filled with a compressible gas which, when said termination is not submerged in liquid, may exchange through said termination with the gas in said container thereby permitting motion of said element under the urging of said source of pulsating force; and when said termination is submerged in the liquid in said container, liquid closing said termination prevents gas in said duct from continued exchange with gas in said container, the frequency of said source of pulsating force being such to permit only minor pulsating displacement of the liquid closing said termination, whereby the gas in said duct is substantially prevented from displacement at said termination when said termination is closed by liquid, and said gas in said duct correspondingly opposes displacement of said element under the urging of said source of pulsating force.

=0 i K i UNETED Tia ES PArENT CFFICE F CGRRECTKON 3,625,636 Dated December 7, 1971 Patent No.

Inventor(s) ROBERT E L N It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below: On the title page address of Inventor "Roseamond" should be --Rosamond-- lColumn 3, line 63 After "and" insert --seal-- Column 3, line 63 "a" should be --an- {Column 4, line 44 I "an" should be -and Column 5, line 41 "HOwever" should be --However-- Column 7, lines 34 and 35 *Cancel "and the emitter of transistor 166 is connected to lead 20" Column 9, line 69 (Claim 2) "ll" should be -7-- Column 10, line 18 (Claim 7) Cancel "containing" Column 10, lines 67 and 68 (Claim 18) Cancel "fluid communication with said" Column 11, lines 33 and 34 (Claim 20) Cance L "including a hous ing having a bore having one end in fluid communication" Column 11, line 39 (Claim 20) "in" should be --and- Signed and sealed this 21st day of November 1972.

(SEAL) Attest:

EDWARD MJLETCHERJR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents 

1. Apparatus comprising: a duct having a termination at a location in a container containing liquid and a compressible gas above said liquid, said termination being in fluid communication with said liquid and may or may not be submerged by said liquid according to the level of the liquid surface in said container; a reciprocable element in fluid communication with said duct, said reciprocable element being in fluid communication with a compressible gas in said duct during normal operating conditions; and a source of pulsating force adapted to urge said element in reciprocation, said source including electromechanical means responsive to a varying current for urging said element in reciprocation and current varying means connected to said electromechanical means for supplying a varying current to said electromechanical means, said varying current varying at such a frequency that said reciprocable element is urged to reciprocate at such a rate as to apply a pulsating force on the fluid closing the termination end of said duct so that when the termination end of said duct is substantially submerged in liquid the pulsating force on the liquid closing the termination does not substantially displace the liquid closing the termination thereby impeding displacement of gas within said duct and impeding reciprocation of said element, and when the termination end of said duct is not substantially submerged in liquid the compressible gas in the duct is vented through said termination to the compressible gas above the level of the liquid surface in said container and said element is not substantially impeded from reciprocation.
 2. Apparatus according to claim 11 wherein said duct is in fluid communication with the opposite side of said element from said reservoir, and outlet means in fluid communication with the same side of said element as said reservoir, said outlet means being in fluid communication with said container.
 3. Apparatus according to claim 1 wherein said duct ascends from the level of liquid in said container.
 4. Apparatus according to claim 1 wherein said duct is disposed in an attitude which lies in the range from one in which the termination is located vertically below the point of fluid communication of the duct with the reciprocable element to one in which the terminAtion is located approximately at the same horizontal level as the point of fluid communication of the duct with the reciprocable element.
 5. Apparatus according to claim 1 further including second duct means having a termination at a location in said container in communication with said liquid and which may or may not be submerged by said liquid according to the level of the liquid surfaces in said container, said second duct means being in fluid communication with said reciprocable element.
 6. Apparatus according to claim 5 wherein said second duct means is in fluid communication with the opposite side of said reciprocable element from the first-named duct.
 7. Apparatus according to claim 1 further including a reservoir, containing liquid pump means for regulating flow of liquid between said reservoir and said reciprocable element, said pump means including a housing having a bore having one end in fluid communication with said reservoir and the other end in fluid communication with said reciprocable element, piston means slidably mounted in said bore and coupled to said element for reciprocation with said element, seal means, and bias means for biasing said seal means against said piston means to provide a fluid seal between said piston means and said bore.
 8. Apparatus according to claim 7, further including a valve seat in said bore between said piston means and said reservoir, valve means in said bore adapted to seal against said valve seat, and second bias means for biasing said valve means against said valve seat.
 9. Apparatus according to claim 8 wherein said piston means is loosely coupled to said element so that said piston means does not reciprocate with minor fluctuations of said element.
 10. Apparatus according to claim 7 wherein said piston means is loosely coupled to said element so that said piston means does not reciprocate with minor fluctuations of said element.
 11. Apparatus according to claim 1 wherein said electromechanical means includes a solenoid having a winding in electrical communication with said current varying means, a core magnetically coupled to said winding for urging said element in one direction upon energization of said winding, and bias means urging said element in the opposite direction.
 12. Apparatus according to claim 11 wherein said bias means is a spring.
 13. Apparatus according to claim 11 wherein said current varying means includes astable multivibrator means adapted to be connected to a source of current, and switch means operable by said multivibrator means for intermittently connecting said source of current to said winding.
 14. Apparatus according to claim 13 wherein said switch means is a transistor.
 15. Apparatus according to claim 13 wherein said switch means is a controlled rectifier.
 16. Apparatus according to claim 15 wherein said controlled rectifier has a controllable element, and delay means connected to said controllable element and said multivibrator means.
 17. Apparatus according to claim 13 further including means connected to said winding for dissipating current surges.
 18. A system for regulating the level of liquid in fluid communication with said a container comprising a duct having a termination at a location in said container in communication with said liquid and which may or may not be submerged by said liquid according to the level of the liquid surface in said container, a reservoir containing liquid, a reciprocable element in fluid communication with said duct, and a source of pulsating force adapted to urge said element in reciprocation, the improvement comprising: pump means controlling fluid communication between said reservoir and said element, said pump means including a housing having a bore having one end in fluid communication with said reservoir and the other end in fluid communication with said element, piston means slidably mounted in said bore and coupled to said element for reciprocation with said element, seal means, and bias means for biasing said seal mEans against said piston means to provide a fluid seal between said piston means and said bore, said piston means being loosely coupled to said element so that said piston means does not reciprocate with minor fluctuations of said element.
 19. Apparatus according to claim 18 further including a valve seat in said bore between said piston means and said reservoir, valve means in said bore adapted to seal against said valve seat, and second bias means for biasing said valve means against said valve seat.
 20. A system for regulating the level of liquid in a container comprising a first duct having a termination at a first location in said container in communication with said liquid and which may or may not be submerged by said liquid according to the level of the liquid surface in said container at said first location, a second duct having a termination at a second location in said container in communication with said liquid and which may or may not be submerged by said liquid according to the level of the liquid surface in said container at said second location, a reservoir containing liquid, a reciprocable element in fluid communication with said first and second ducts, and a source of pulsating force adapted to urge said element in reciprocation, the improvement comprising: pump means controlling fluid communication between said reservoir and said element, said pump means including a housing having a bore having one end in fluid communication including a housing having a bore having one end in fluid communication with said reservoir and the other end in fluid communication with said element, piston means slidably mounted in said bore and coupled to said element for reciprocation with said element, seal means, and bias means for biasing said seal means against said piston to provide a fluid seal between said piston means in said bore.
 21. Apparatus according to claim 20 wherein said second duct means is in fluid communication with the opposite side of said element from the first-named duct.
 22. A system for regulating the level of liquid in a container comprising a duct having a termination at a location in said container in communication with said liquid and which may or may not be submerged by said liquid according to the level of the liquid surface in said container, a reservoir containing liquid, a reciprocable element in fluid communication with said duct, a source of pulsating force adapted to urge said element in reciprocation, said duct being in fluid communication with the opposite side of said element from said reservoir, and outlet means in fluid communication with the same side of said element as said reservoir, said outlet means being in fluid communication with said container, the improvement comprising: pump means for controlling fluid communication between said reservoir and said element, said pump means including a housing having a bore having one end in fluid communication with said reservoir and the other end in fluid communication with said element, piston means slidably mounted in said bore and coupled to said element for reciprocation with said element, seal means, and bias means for biasing said seal means against said piston means to provide a fluid seal between said piston means and said bore.
 23. Apparatus comprising: a container adapted to hold a body of liquid having a liquid level surface and a compressible gas above that surface, a reciprocable fluid displacement element, a source of pulsating force adapted to urge said element in reciprocation, including a. electromechanical force means and b. current varying means for supplying a pulsating electric current to said electromechanical means, a duct adapted to receive the displacement of said element and having an open termination in said container which may or may not be submerged by said liquid according to the level of said surface, said duct being normally filled with a compressible gas which, when said termination is not submerged in liquid, may exchange through said tErmination with the gas in said container thereby permitting motion of said element under the urging of said source of pulsating force; and when said termination is submerged in the liquid in said container, liquid closing said termination prevents gas in said duct from continued exchange with gas in said container, the frequency of said source of pulsating force being such to permit only minor pulsating displacement of the liquid closing said termination, whereby the gas in said duct is substantially prevented from displacement at said termination when said termination is closed by liquid, and said gas in said duct correspondingly opposes displacement of said element under the urging of said source of pulsating force. 